A variety of different stents for use in angioplasty procedures have been developed in which a therapeutic drug agent is coated onto the stent prior to use. In particular, coated stents have been developed that include therapeutic drug agents that are intended to help prevent renarrowing of the arteries, also known as restenosis, after an angioplasty procedure has been performed.
Generally, the stents are precoated with the therapeutic drug agents prior to packaging of the stent and its associated catheter delivery system so that the stent can be removed from its package and used directly in a procedure. However, treated stents often present problems associated with drug administration because of the presence of the therapeutic drug agent. For example, for a drug to be administered effectively, the integrity of the active component of the drug as well as the drug's effective dosage should be maintained. Certain drugs may be adversely affected by reacting with various gases that may be found in the atmosphere of the package, such as oxygen, moisture vapor, and the like. As a result, it is generally desirable to control and/or minimize the level of such gases in the package.
Additionally, it is necessary to sterilize the treated stents during the packaging process. Common forms of sterilization include irradiation; autoclaving, and treatment with a sterilizing gas, such as ethylene oxide. Typically, treatment with a sterilizing gas is used to sterilize treated stents. One of the most common forms of sterilizing such stents involves a multi-step process in which the treated stent is first placed in a flexible packaging bag formed of a breathable material, such as paper or a nonwoven sheet material, such as Tyvek®. This packaging bag along with the stent is then treated with a sterilizing gas. Thereafter the packaging bag and the stent are placed into an outer bag comprising a barrier film. The treated stent and the packaging bag are then typically sealed in the barrier bag until removed for use. Such a packaging process is typically undesirable because it requires multiple steps and two separate and distinct packaging bags. Other packaging systems for coated stents have typically comprised a thermoform tray insert in a foil pouch, or a thermoform tray having a barrier lid in a foil pouch, into which the stent is vacuum packed.
Such conventional packaging for stents generally does not provide for sufficient control of gases in the package. Without such appropriate control, the efficacy of the drug and/or drug coating may be reduced. Moreover, these packages tend to be heavier than desirable, they utilize more material and they require more operator handling time to pack and so are more labor intensive to produce.